My first attempt at a spriograph

After screwing up twice on my blu-ray I had three drives without lasers in them, so I pulled out the drive opening motors and glued some mirrors onto them. I taped them down to decks of cards, and wired them up with pots 10k pots (WAY too high resistance. The motors stop completely after about an 8th of a turn!) and set up one of my DX 70mW lab lasers.

The result is a 3 motor spiro with VERY touchy motor speed control. In fact, the entire setup is so sketchy that I'm surprised it's working at all. But hey, I put in some snazzy music.

http://www.youtube.com/watch?v=DErPtjMN-rM

yay I'm not alone!!
I too had this problem with the pots being way to sensitive, 1/8 of a turn..etc.. but with a 1k pot it was even worse, it seemed the more resistance i had the less sensitive it was. making me think if i had a 50k or 100k pot it would be fine. tell me if you get it working right, cuz I too am trying to work something out.

also, did you tilt your mirrors? or keep them completely flat? I cant seem to get that "3rd dimension" yet, and it looks like you havnt either. both you and me are in the same spot, i wish us both luck!

edit: O and awesome music btw! haha, what's it called?

Not a bad job at all. Looks like one of the mirrors is warped a bit. Anyway, I'd recommend no more than 1k pots.

Kenom said:

Not a bad job at all.  Looks like one of the mirrors is warped a bit.  Anyway, I'd recommend  no more than 1k pots.

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no more than 1k pots??? then my spirograph was a total failure... i tried 1k and it was WAY to sensitive, i mean it was an on/off, there wasn't even anything inbetween, then i tried 5k and it was a bit better 1/16 of pot could be turned before it turned off, then 10k about 1/8 of it could be turned. so it seems the higher i go the better.

well it also depends on the motors your using as well as the power supply. i'm using 3 9v motors off one lead acid 12v battery. I'm using 100 ohm pots and it seems to work fine.

I'm using some 12V normal sized PC fans, 12V power supply. i guess I'll have to try higher pots.

Ahhh that's why I would think. I'm using honest brush motors. those brushless are very little draw.

I plan to eventually get a few different types of pots and test a bunch to see what gets the best results. The motors I am using are brushless motors and run on 5V. So with 10k pots you can imagine I don't get much range out of them!

My spirograph uses 3 of the motors that push out the tray in a cd drive, wired in parallel to a 9v battery. All I need are 100ohm pots and they are just fine

lol it's so easy for everyone...

Event Horizon are your mirrors glued strait on flat or at a slight angle?

It's always at a slight angle. If it's perfectly flat then there's no point with it, it would just be a dot on the wall, spinning mirror or not.

FireMyLaser said:

It's always at a slight angle. If it's perfectly flat then there's no point with it, it would just be a dot on the wall, spinning mirror or not.

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thats what i tried to tell Nikokapo but he assures me it's completely flat!!

whats the benefit of a 3 motor spiro compared to a 2?

thesk8nmidget said:

whats the benefit of a 3 motor spiro compared to a 2?

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apparently the 3rd mirror shows a 3rd dimension... which I havnt seen yet, but I havnt worked on my Spirograph in about a week, I will soon.

it gives you a bit more dimension to your graphics when using 3 mirrors. The basic 2 mirror is cool but you won't get the detailed effects from a 2 that you get with 3.

Essentiallly your trying for very little tilt. By trying to mount it flush, your going to fail. but that fail is a good thing. it's not so off center that the mirror is going to come loose while turning and your beam isn't going to go so wild it will spill off the other mirrors.

In my illustration below you can see 3 different colors. Each represents an angle of the tilt on a mirror and the effect it will have on a laser.

Green represents a flat mirror with no tilt. You can see in the illustration that it easily bounces from one mirror to the next with no effect on the laser at all.

Red represents a mirror with correct tilt to it. Very close to flat. As represented in the illustration it causes the beam to vary in it's path by a certain angle. usually the less the better to a point. While it varies, it still stays on the entire surface of the mirror. Also the size of the "image" from the spyrograph is smaller and more defined.

Blue represents a mirror with TOO much tilt. The angle of reflection has increased and it's actually causing the laser to sometimes overshoot the second mirror and you have no output at all. When it does shine off the second mirror, it's output is going to be VERY large and your images are not so well defined.

Hope this clears things up.